1. Field of the Invention
The present invention relates generally to medical apparatus and methods. In particular, the present invention relates to methods and devices for delivering carbon dioxide and other gases to patients for relieving symptoms associated with headache (e.g., migraine headaches, tension-type headaches, cluster headaches), jaw pain, facial pain (e.g., trigeminal neuralgia), allergies (rhinitis and conjunctivitis), asthma, nervous disorders (e.g., epilepsy, Parkinson's), and other common ailments.
A walk through the headache and allergy section of any pharmacy quickly reveals that there is wide spread interest in remedies for relieving symptoms commonly associated with headaches, allergies, asthma, and other common ailments. The commonly available therapies include oral medicines, nasal sprays, oral inhalers, nasal inhalers, eye drops, and nose drops, and probably other devices and approaches that have been developed over the years. Still more possible therapies are available from the pharmacy with a prescription from a patient's doctor (e.g., injectables, inhalables). Despite the very large number of therapies which are available, no one therapy meets all patient needs, and many of the therapies suffer from very significant shortcomings. For example, present day therapies are slow-acting, have numerous adverse side effects (e.g., nausea, drowsiness, rebound headache from analgesic overuse, rebound congestion from decongestant overuse, dizziness, sedation, addiction, and numerous others), have low efficacy, and are contraindicated for a large portion of patients (e.g., those with hypertension, coronary artery disease, cerebrovascular disease, peptic ulcers, pregnancy, concurrent medications that would interact, children, elderly, and others). Suffice it to say that there is a continuing interest in providing improved methods and apparatus for treating such common symptoms and ailments.
The use of diluted carbon dioxide by inhalation for treating symptoms related to headaches, allergies, asthma, nervous disorders, and other common ailments was demonstrated in the 1940's and 1950's. The treatment protocols generally rely on breathing masks or other equipment for delivering relatively large volumes of dilute carbon dioxide for the patient to inhale through the mouth and/or the nose into the lungs until they become unconscious. The efficacy of this treatment depends upon the systemic effects of the inhaled gas and therefore require large volumes of gas. Typical carbon dioxide volumes inhaled were in the range from 0.5 to 25 liters of 30% to 70% carbon dioxide diluted in oxygen during a single treatment which was repeated several times a week for 25 to 50 treatments. While the use of inhaled carbon dioxide has proven to be quite effective for a number of indications, the wide spread use of carbon dioxide delivered in this manner never became popular. It is limited by the necessity of making the patient unconscious, the length of the treatment time and course, and the necessarily large, bulky non-portable gas cylinders and physician administration it requires. Most prior systems are so large and heavy they must be wheeled about using a dolly or a cart, and thus do not lend themselves to use outside of the hospital or home. While hand-held carbon dioxide dispensers have been proposed (for other purposes such as the treatment of hyperventilation), they are designed to deliver large volumes of dilute carbon dioxide for inhalation.
For these reasons, it would be desirable to provide improved apparatus and methods for treating the symptoms normally associated with headaches, allergies, asthma, and the like. Such apparatus and methods should provide small volumes of gas for convenient use away from the home, substantially immediate relief of symptoms, safety with few or no side effects, efficacy without requiring unconsciousness, efficacy in a large number of patients, therapy for those contraindicated for present day therapies, therapy without interaction with concurrent medications, low cost, a long life (in at least some embodiments), and permit the patient to administer the therapy and adapt the product usage for maximum comfort and effectiveness. At least some of these objectives will be met by the inventions described hereinafter.
2. Description of the Background Art
U.S. Pat. No. 3,776,227, describes a hand-held dispenser that delivers dilute carbon dioxide intended for the treatment of hyperventilation by inhalation. In addition, this hand-held dispenser is not designed to deliver carbon dioxide at high concentrations which are unbreathable. Other inhalation devices, systems, and methods for delivering carbon dioxide and other gases and aerosols to patients are described in U.S. Pat. Nos. 3,513,843; 3,870,072; 3,974,830; 4,137,914; 4,554,916; 5,262,180; 5,485,827; and 5,570,683.
Gas therapy for the treatment of headaches, allergies, asthma, and other conditions as well as associated physiology is described in the following references in the medical literature: